1. Field of the Invention
In general, this invention relates to blood glucose measuring devices and techniques. More particularly, this invention relates to systems and methods that can measure blood glucose in the body without the need to draw a blood sample.
2. Prior Art Description
Diabetes is a chronic disease without cure. Over twenty five million people in the United States of America have diabetes. Diabetes is the seventh leading cause of death in the United States. Currently, diabetes is estimated to cost the United States health care system over one-hundred billion dollars annually.
Diabetes creates high blood glucose levels due to a deficiency of insulin production and action. This failure leads to hyperglycemia. Persistent hyperglycemia causes a variety of serious symptoms and life threatening long term complications such as dehydration, diabetic coma, cardiovascular disease, and poor blood circulation.
Many diabetics are required to take insulin in order to control the glucose levels in their blood. However, having insulin levels in the blood that are too high are just as dangerous as having insulin levels in the blood that are too low. Consequently, it is critical that diabetics who use insulin precisely monitor the level of glucose in their bodies.
The most common and accurate glucose monitoring techniques require that a blood sample be drawn from the body. This is typically done by pricking the skin with a needle or lancet to obtain a small droplet of blood. The blood is placed upon a chemically treated strip of paper. The strip of paper is then placed in a glucometer, which tests the blood and provides a glucose level reading.
Pricking the skin can be painful. Areas of the skin can also experience increased sensitively to pain if those areas are repeatedly pricked over long periods of time. Furthermore, many diabetics have blood circulation problems. As a result, these diabetics can only draw blood from certain parts of the body, such as the fingertips, where good blood flow remains. Unfortunately, the areas of the body that have good blood flow often correspond to the areas of the body that have a high concentration of nerve endings, thus increasing the pain associated with obtaining such a blood sample. The result often is that diabetics are deterred from testing and consequently test their blood glucose levels far less often than they should.
For the reasons stated above, there has been a long standing need for a glucose monitoring device that can detect the level of glucose in a diabetic without the need for a drawn a blood sample. In the prior art, certain devices have been produced that claim that they can meet this need. For instance in U.S. Patent App. Pub. No. 2010/0112614 to Axelrod, entitled Coupled Antenna Impedance Spectroscopy, a methodology is presented for measuring blood glucose levels. However, the technique does not produce accurate results in comparison to common blood drawn testing techniques. More importantly, such methodologies require the use of a spectroscope. Consequently, such testing systems are limited to use in hospitals and labs that have spectroscopes. Such testing systems cannot be made into low-cost portable devices using known technologies.
The present invention uses a small, inexpensive microwave resonance chamber to detect blood glucose levels from the tip of a diabetic's finger. Microwave resonance chambers have been in existence for over seventy-five years as is evidenced by U.S. Pat. No. 2,233,263 to Linder, entitled Resonant Cavity Oscillator. It is well known that solid-state oscillators that employ an oscillating element in a resonant cavity produce an oscillation frequency that is dependent upon the physical dimensions of the cavity. The oscillation frequency produced is so sensitive to cavity size that the oscillation frequency is affected by minute dimensional changes caused by changes in temperature. As a result, modern oscillator resonance chambers are designed to compensate for changes caused by temperature changes. See U.S. Pat. No. 4,011,527 to Havens, entitled Temperature Compensated Microwave Cavity Transistor Oscillator.
Although many designs of microwave resonance chambers exist in the prior art, no such chamber has ever been used to test for blood glucose levels.
A need therefore exists for a blood glucose meter that can be manufactured into a low-cost portable device. A need also exists for a blood glucose meter that has a monitoring accuracy that is at least as good as, or better than, the accuracy of traditional drawn blood glucose meters. These needs are met by the present invention as described and claimed below.